Limestone in rice cultivated on highland soils of the southern Amazon

Abstract

Rice is grown in almost all Brazilian regions, being a crop of great socioeconomic importance for small farmers in southern Amazon. The objective in this work was to evaluate the agronomic performance of rice in two highland soils of Humaitá region, submitted to liming. Samples of the Haplic Cambisol and Oxisol soils were incubated for 30 days with the equivalent of 0, 2, 4, 6, 8 and 10 t ha^-1 with 98% ECCE limestone and then cultivated with rice in a greenhouse. A completely randomized design with 6 treatments (doses) and 4 repetitions was used. The following characteristics were evaluated: plant height, shoot dry mass, number of tillers and panicles per plant, total number of grains, normal and malformed grains per panicle, and normal and malformed grain mass per panicle. Liming reduces the development of rice plants grown in the Haplic Cambisol, while in the Oxisol the plants had better performance when applied the equivalent of 5.2 t ha^-1 of limestone.